ar71xx: fix bad "proto" references in default network configuration

This change was originally meant to go along with the ucidef_set_interface()
fixup.

Fixes: 7e664b7c2d ("base-files: fix ucidef_set_interface() protocol selection")
Fixes: 85048a9c1f ("base-files: rework _ucidef_set_interface to be more generic")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

target/linux/ar71xx/base-files/etc/board.d/02_network

@@ -402,7 +402,7 @@ ar71xx_setup_interfaces()
 			"0@eth0" "1:lan:4" "2:lan:3" "3:lan:2" "4:lan:1" "5:wan"
 		;;
 	ew-balin)
-		ucidef_set_interface "usb2" ifname "usb0" proto "static"
+		ucidef_set_interface "usb2" ifname "usb0" protocol "static"
 		ucidef_add_switch "switch0" \
 			"0@eth0" "5:lan:4" "4:lan:5" "3:wan"
 		;;
@@ -469,7 +469,7 @@ ar71xx_setup_interfaces()
 		;;
 	tellstick-znet-lite)
 		ucidef_set_interface_wan "eth0"
-		ucidef_set_interface "wlan" ifname "wlan0" proto "dhcp"
+		ucidef_set_interface "wlan" ifname "wlan0" protocol "dhcp"
 		;;
 	tl-mr3420-v2|\
 	tl-wr841n-v8|\